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## Homework Statement

A .20 kg hockey puck is launched up a metal ramp that is inclined at a 30.0 degree angle. The coefficients of static and kinetic friction between the hockey puck and the metal ramp are

*M*

_{s}= .40 kg and

*M*

_{k}=.30 kg , respectively. The puck's initial speed is 35.0 m/s. What is the magnitude of the acceleration of the puck on the ramp?

## Homework Equations

F= ma

## The Attempt at a Solution

N= Nj

Fgrav= mg(cos 30- sin 30)

Friction=

*M*

_{k}N

In the j direction the forces are:

N-mgsin(30)=0

N= -1.94

In the i direction the forces are:

mgcos(30) +

*M*

_{k}N=ma

a= (mgcos(30)+

*M*

_{k}N)/ m =a

then when I plug in all of the given numbers I get -1.4.

I have tried this problem a bunch of times and cannot get anywhere close to the correct answer. What am I doing wrong?